The majority of coastal sediment carbon cycling studies have focused on contributions from autochthonous photosynthetic marine and allocthonous terrigenous inputs. However, hydrocarbons produced within deep sediment through thermochemical and microbiological conversions can significantly contribute to cycling of carbon, especially in shallower sediments and water column. Stable carbon isotope ratios indicative of petroleum and methane (CH4) origins are found in bacterioplankton biomarkers. In a related study in the Northeastern Pacific Ocean, it has been estimated that sediment methane contributes about 28% of the carbon to the water column dissolved organic carbon (DOC) pool and is a significant energy resource for biological activity in many coastal regions worldwide. Methane also contributes to carbon pools within shallow sediments. → Go to Full Report
